With the more and more challenging marketing and customer demands, technologies which can ensure the better quality, cost performance, time to market…and etc., are always what we would absolutely look for. This is the same for the injection molding industry — As we know, the cooling time often occupies of 70% of the injection cycle and critical for most of the warpage issues. When process optimization and quality improvement is a priority, we always try to find some lights in this cooling stage.

The customer of this successful case study, Gplast, is from Coimbatore, India. With more than three decades of experience and expertise in Tool and Die making, injection molding and die casting, Gplast is very well known for its achievements in Electronics, Precision Machine Tools and Transport.

Warpage is the first priority since product quality is affected a lot. However, due to the geometric limitation, revising process conditions or other efforts could not really lead to satisfying enhancements. Since conformal cooling is one of the key advantages of Gplast, it is decided to use the true and full 3D Computer Assisted Engineering (CAE) tool to evaluate the effectiveness of the customized cooling layout designs.

Fig. 1. Cooling channels and mold base – true 3D mesh model for simulation accuracy

One of the important concerns in this case is – the traditional 1D runner or cooling layout is not capable for simulating correct results due to theoretical and functional limitations.

After using Moldex3D/Solid for complete simulation of the original cooling layout design, the analysis result shows the internal temperature is quite high and there is a region with heat accumulation. The mold temperature difference results in the non-uniform shrinkage – finally it leads to the warpage problem which is related with thermal effect.

Fig. 2. Original cooling layout (left) and the mold temperature difference (right)

To improve this warpage problem, conformal cooling design is applied for solutions. Moldex3D is again used for performing reliable analysis via complete and high-performance 3D simulations. After revising the cooling system, the mold temperature difference is greatly reduced from 40°C to 6°C – about a 85% improvement. In addition, the temperature of the corner region (with exceeding heat in original design) is much more uniform.

Fig. 3. Revised cooling layout (left) and the mold temperature difference (right)

Compared with the original design, the Z-displacement of the revised cooling system is reduced 25.6%. The target of the cooling system optimization is successfully reached by such an outstanding warpage improvement. In this case, Moldex3D simulation results are highly consistent with the real injected parts, and prove

Fig. 4. Warpage of original design – real injected part and simulation result

Fig. 5. Warpage results of revised design with conformal cooling –real injected part and simulation result

Behind the Scene

This is just one of many successful cases done in Gplast. The synergy of true 3D Simulation and conformal cooling design capability proves not only the quality issues like warpage can be effectively eliminated, but also the product development cycle time would be improved. The true 3D Simulation plays an important role – assists to identify the connections between revised cooling designs and the results. Without these analysis results, it would be difficult to precisely evaluate the contribution of different conformal cooling layouts. The application of Moldex3D brings the real confidence for both product development and the performance of conformal cooling designs.

In short, the real performances of this case include:

• Warpage Improvement
• Cycle time reduction (Annual: about 400,000 seconds are saved) and productivity enhancement
• Long-term unsolved quality deviation is fully resolved.
• Recycling of cooling fixture is eliminated and profitability is enhanced.

About Conformal Cooling

Conformal cooling is defined as the ability to create cooling / heating configurations within a tool that essentially follows the contour of the tool surface or deviates from that contour as thin / thick sections of the part may dictate for optimal thermal management. The objective typically is to cool or heat the part uniformly. Conformal cooling provides a tremendous advantage in mold tooling through significant reductions in cycle times. Other than the obvious piece-cost savings, other tangible benefits include tool, equipment and floor space savings. (Source: Gplast)